Gastric Mucosal Atrophy Impedes Housekeeping Gene Methylation in Gastric Cancer Patients / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Helicobacter pylori infection induces phenotype-stabilizing methylation and promotes gastric mucosal atrophy that can inhibit CpG-island methylation. Relationship between the progression of gastric mucosal atrophy and the initiation of CpG-island methylation was analyzed to delineate epigenetic period for neoplastic transformation. MATERIALS AND METHODS: Normal-appearing gastric mucosa was biopsied from 110 H. pylori–positive controls, 95 H. pylori–negative controls, 99 gastric cancer patients, and 118 gastric dysplasia patients. Gastric atrophy was assessed using endoscopic-atrophic-border score. Methylation-variable sites of eight CpG-island genes adjacent to Alu (CDH1, ARRDC4, PPARG, and TRAPPC2L) or LTR (MMP2, CDKN2A, RUNX2, and RUNX3) retroelements and stomach-specific TFF3 gene were analyzed using radioisotope-labeled methylation-specific polymerase chain reaction. RESULTS: Mean ages of H. pylori–positive controls with mild, moderate, and severe atrophy were 51, 54, and 65 years and those of H. pylori–associated TFF3 overmethylation at the three atrophic levels (51, 58, and 63 years) tended to be periodic. Alu-adjacent overmethylation (50 years) was earlier than TFF3 overmethylation (58 years) in H. pylori–positive controls with moderate atrophy. Cancer patients with moderate atrophy showed late Alu-adjacent (58 years) overmethylation and frequent LTR-adjacent overmethylation. LTR-adjacent overmethylation was frequent in cancer (66 years) and dysplasia (68 years) patients with severe atrophy. CONCLUSION: Atrophic progression is associated with gastric cancer at moderate level by impeding the initiation of Alu-adjacent methylation. LTR-adjacent methylation is increased in cancer patients and subsequently in dysplasia patients.

DNA Methylation as Surrogate Marker For Gastric Cancer

Stomach cancer remains, stubbornly, highly prevalent in East Asia. Still, stomach cancer has few biomarkers by which it can be predicted. Helicobacter pylori infection, a known carcinogen of stomach cancer, usually goes undetected prior to cancer diagnosis, due to the poor mucosal environments that its related gastric atrophy causes. We propose, herein, an endoscopic-biopsy-based cancer-predicting DNA methylation marker. We semi-quantitatively examined the methylation-variable sites near the CpG-island margins by radioisotope-labeling methylation-specific polymerase chain reaction in association with H. pylori, which increases age-related over-methylation in CpG islands of gastric mucosa. These age-related methylation patterns of the transitional-CpG sites are proposed as useful surrogate markers for stomach cancer. It would be helpful for setting the optimal screening interval for high-risk subjects as well as for estimating the prognosis and the predictability for recurrence of early gastric cancer in patients having undergone endoscopic submucosal dissection. New screening-interval guidelines for gastric cancer should be suggested considering individual risk based on age, severity of atrophy, H. pylori status, and DNA methylation pattern.

DNA Methylation Patterns of Ulcer-Healing Genes Associated with the Normal Gastric Mucosa of Gastric Cancers

Recent evidence suggests that gastric mucosal injury induces adaptive changes in DNA methylation. In this study, the methylation status of the key tissue-specific genes in normal gastric mucosa of healthy individuals and cancer patients was evaluated. The methylation-variable sites of 14 genes, including ulcer-healing genes (TFF1, TFF2, CDH1, and PPARG), were chosen from the CpG-island margins or non-island CpGs near the transcription start sites. The healthy individuals as well as the normal gastric mucosa of 23 ulcer, 21 non-invasive cancer, and 53 cancer patients were examined by semiquantitative methylation-specific polymerase chain reaction (PCR) analysis. The ulcer-healing genes were concurrently methylated with other genes depending on the presence or absence of CpG-islands in the normal mucosa of healthy individuals. Both the TFF2 and PPARG genes were frequently undermethylated in ulcer patients. The over- or intermediate-methylated TFF2 and undermethylated PPARG genes was more common in stage-1 cancer patients (71%) than in healthy individuals (10%; odds ratio [OR], 21.9) and non-invasive cancer patients (21%; OR, 8.9). The TFF2-PPARG methylation pattern of cancer patients was stronger in the older-age group (> or =55 yr; OR, 43.6). These results suggest that the combined methylation pattern of ulcer-healing genes serves as a sensitive marker for predicting cancer-prone gastric mucosa.

Loss of Heterozygosity on Chromosome 15q15 Near Thrombospondin-1 Gene in Breast Carcinomas

BACKGROUND: Chromosome 15q15 near the thrombospondin-1 (THBS-1) gene may be associated with tumor progression and metastasis. To clarify the potential role of the15q15 region in progression of breast carcinoma, we investigated the loss of heterozygosity (LOH) and the microsatellite instability (MSI) status of chromosome 15q15. Methods : LOH and MSI were detected in 84 breast carcinoma specimens using PCR-based microsatellite analysis with three microsatellite markers. METHODS: LOH and MSI were detected in 84 breast carcinoma specimens using PCR-based microsatellite analysis with three microsatellite markers. RESULTS: Of 77 breast carcinomas containing the heterozygous alleles, 25 (32%) showed LOH in at least one microsatellite marker. Partial LOH and total LOH were detected in 14 (18.27%) and 11 (14.3%) cases. The total LOH were inversely correlated with node metastasis. A single LOH at D15S514 was inversely correlated with nuclear grade and a single LOH at the D15S129 allele was associated with increased expression of the THBS-1 gene. MSI-positive breast carcinomas detected in 14 (17%) cases showed no correlation with any clinicopathologic feature. CONCLUSIONS: These results indicate that loss of the chromosome 15q15 region delays the progression of breast carcinoma because the magnitude of LOH is large and involves the THBS-1 gene and additional genetic elements. The genes located on chromosome 15q15 probably play a tissue-type-dependent role in malignant growth of the tumor.

DNA Methylation and Expression Patterns of Key Tissue-specific Genes in Adult Stem Cells and Stomach Tissues

CpG-island margins and non-island-CpG sites round the transcription start sites of CpG-island-positive and -negative genes are methylated to various degrees in a tissue-specific manner. These methylation-variable CpG sites were analyzed to delineate a relationship between the methylation and transcription of the tissue-specific genes. The level of tissue-specific transcription was estimated by counting the number of the total transcripts in the SAGE (serial analysis of gene expression) database. The methylation status of 12 CpG-island margins and 21 non-island CpG sites near the key tissue-specific genes was examined in pluripotent stromal cells obtained from fat and bone marrow samples as well as in lineage-committed cells from marrow bulk, stomach, colon, breast, and thyroid samples. Of the 33 CpG sites examined, 10 non-island-CpG sites, but none of the CpG-island margins were undermethylated concurrent with tissue-specific expression of their nearby genes. The net methylation of the 33 CpG sites and the net amount of non-island-CpG gene transcripts were high in stomach tissues and low in stromal cells. The present findings suggest that the methylation of the non-island-CpG sites is inversely associated with the expression of the nearby genes, and the concert effect of transitional-CpG methylation is linearly associated with the stomach-specific genes lacking CpG-islands.

Chromosomal Losses are Associated with Hypomethylation of the Gene-Control Regions in the Stomach with a Low Number of Active Genes

Transitional-CpG methylation between unmethylated promoters and nearby methylated retroelements plays a role in the establishment of tissue-specific transcription. This study examined whether chromosomal losses reducing the active genes in cancers can change transitional-CpG methylation and the transcription activity in a cancer-type-dependent manner. The transitional-CpG sites at the CpG-island margins of nine genes and the non-island-CpG sites round the transcription start sites of six genes lacking CpG islands were examined by methylation-specific polymerase chain reaction (PCR) analysis. The number of active genes in normal and cancerous tissues of the stomach, colon, breast, and nasopharynx were analyzed using the public data in silico. The CpG-island margins and non-island CpG sites tended to be hypermethylated and hypomethylated in all cancer types, respectively. The CpG-island margins were hypermethylated and a low number of genes were active in the normal stomach compared with other normal tissues. In gastric cancers, the CpG-island margins and non-island-CpG sites were hypomethylated in association with high-level chromosomal losses, and the number of active genes increased. Colon, breast, and nasopharyngeal cancers showed no significant association between the chromosomal losses and methylation changes. These findings suggest that chromosomal losses in gastric cancers are associated with the hypomethylation of the gene-control regions and the increased number of active genes.

Methylation and Chromosomal Losses in Squamous Cell Carcinoma of the Head and Neck / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Methylation of CpG islands is associated with delayed replication, condensed chromatin and inhibition of transcription initiation in many human cancers. Another concern with regards to CpG methlation is unilateral chromosomal losses in head and neck cancer. In this study, we investigated the extent of chromosomal losses and the status of CpG methylation in head and neck cancer in relation with clinicopathologic factors. SUBJECTS AND METHOD: Both normal mucosa and tumor tissue samples were secured from 17 cases to a total of 34 samples to be examined with a methylation- specific PCR on 15 cancer-linked genes. A total of 29 cases were analyzed for PCR-based loss of heterozygosity (LOH) using a panel of 41 microsatellite markers on 8 chromosomes. RESULTS: The pattern of methylation changes between the paired normal mucosa and tumor site was variable. Of the total of 206 cases examined for the methylation status of non-CpG island, 34 cases showed hypomethylation changes, 26 cases hypermethylation changes, and 31 cases no methylation changes. Regions containting CpG islands had 8 cases showing hypomethylation changes, 17 cases hypermethylation changes, and 31 cases of no methylation changes. The relationship between methylation and lymph node invasion revealed that, in the event of lymph node invasion, p16 downstream 0.7 kbp, p16 upstream 1.0 kbp, and hMLH1 upstream 1.0 kbp showed hypomethylation, whereas BGLAP upstream 4.5 kbp, Runx3 upstream 1.7 kbp, KIAA downstream 0.4 kbp showed hypermethylation. However, the rest of the genes were not changed. In 29 tumor foci, a LOH was found most frequently on the chromosomes 3p, 8p, 9p, and 13q. Interestingly, although other previous reports have not reported the detection of 8p chromosomal loss in head and neck cancer, this study frequently detected 8p chromosomal loss. Chromosomal loss yielded an overall mean value of 4.79+/-2.2 per tumor focus. A special relationship could not be drawn based on the relationship between the methylation and LOH. But in several genes such as p16 and hMLH1, there were differences between the hypomethylation. Genetic instability was raised when hypomethylation increased. CONCLUSION: This study showed that the head and neck cancer and its progression generally need the proper level of chromosomal losses to accomplish cancer progression or development. Methylation pattern and LOH might be important rules and target event in head and neck cancer. In the future, experiments to find the point of genetic modification will help the way to prevent the cancer.

The Extent of Chromosomal Losses and the Status of CpG Methylation in Squamous Cell Carcinoma of the Head and Neck / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Carcinogenesis is known to arise as a result of the accumulation of genetic alterations including unilateral chromosomal losses and epigenetic modification. In this study, we investigated the extent of chromosomal losses and the status of CpG methylation in squamous cell carcinoma of the head and neck in relation to the clinicopathologic factors. SUBJECTS AND METHOD: A total of 20 tumor foci from 12 cases were examined wtih PCR-based loss of heterozygosity (LOH) analysis using a panel of 41 microsatellite markers on 8 chromosomes and a total of 10 tumor foci from 5 cases were examined with methylation-specific PCR on 2 extragenic regions of the 3 cancer-linked genes. RESULTS: In 20 tumor foci, LOH was found most frequently on the chromosome 8p. Multiple tumor foci of a given case had the same or a similar extent of chromosomal losses and yielded an overall mean value of 5.5 per tumor focus. Even though the tumor foci showed histological homogeneity, they revealed genetical heterogeneity. The relation between methylation changes between the paired normal mucosa and tumor site was variable and 10 tumor sites examined for the methylation status of 6 extragenic regions showed 21 (35%) hypomethylation changes, 6 (10%) hypermethylation changes, and 33 (55%) no methylation changes. The degree of methylation changes indicated the tendency to cluster in the range of U1 and M1 low-grade changes. With respect to relationship between bet methylation changes and clinicopathologic factors, hypomethylation changes were dominant in those cases with increased depth of invasion. CONCLUSION: These results showed that multiple intratumoral foci of the head and neck cancer patients were generally under the influence of a similar level of chromosomal losses and hypomethylation changes.

Relationship Between the Extent of Chromosomal Losses and the Pattern of CpG Methylation in Gastric Carcinomas

The extent of unilateral chromosomal losses and the presence of microsatellite instability (MSI) have been classified into high-risk (high- and baseline-level loss) and low-risk (low-level loss and MSI) stem-line genotypes in gastric carcinomas. A unilateral genome-dosage reduction might stimulate compensation mechanism, which maintains the genomic dosage via CpG hypomethylation. A total of 120 tumor sites from 40 gastric carcinomas were examined by chromosomal loss analysis using 40 microsatellite markers on 8 chromosomes and methylation analysis in the 13 CpG (island/non-island) regions near the 10 genes using the bisulfite-modified DNAs. The high-level-loss tumor (four or more losses) showed a tendency toward unmethylation in the Maspin, CAGE, MAGE-A2 and RABGEF1 genes, and the other microsatellite-genotype (three or fewer losses and MSI) toward methylation in the p16, hMLH1, RASSF1A, and Cyclin D2 genes (p<0.05). The non-island CpGs of the p16 and hMLH1 genes were hypomethylated in the high-level-loss and hypermethylated in the non-high-level-loss sites (p<0.05). Consequently, hypomethylation changes were related to a high-level loss, whereas the hypermethylation changes were accompanied by a baseline-level loss, a low-level loss, or a MSI. This indicates that hypomethylation compensates the chromosomal losses in the process of tumor progression.

Periodic Explosive Expansion of Human Retroelements Associated with the Evolution of the Hominoid Primate

Five retroelement families, L1 and L2 (long interspersed nuclear element, LINE), Alu and MIR (short interspersed nuclear element, SINE), and LTR (long terminal repeat), comprise almost half of the human genome. This genome-wide analysis on the time-scaled expansion of retroelements sheds light on the chronologically synchronous amplification peaks of each retroelement family in variable heights across human chromosomes. Especially, L1s and LTRs in the highest density on sex chromosomes Xq and Y, respectively, disclose peak activities that are obscured in autosomes. The periods of young L1, Alu, LTR, and old L1 peak activities calibrated based on sequence divergence coincide with the divergence of the three major hominoid divergence as well as early eutherian radiation while the amplification peaks of old MIR and L2 account for the marsupial-placental split. Overall, the peaks of autonomous LINE (young and old L1s and L2s) peaks and non-autonomous SINE (Alus and MIRs) have alternated repeatedly for 150 million years. In addition, a single burst of LTR parallels the Cretaceous-Tertiary (K-T) boundary, an exceptional global event. These findings suggest that the periodic explosive expansions of LINEs and SINEs and an exceptional burst of LTR comprise the genome dynamics underlying the macroevolution of the hominoid primate lineage.

Genetic Classification of Breast Cancer based on Unilateral Chromosomal Loss / 한국유방암학회지

PURPOSE: The extent of the loss of heterozygosity (LOH) has been used as the genetic parameter for the classification and staging of some solid tumors. Breast cancers such as ductal carcinoma in situ (DCIS), and invasive and metastatic lesions, are frequently observed to contain heterogeneous tumor foci. To delineate the relation between the LOH and the progression of breast cancers, three successive histological sites in a tumor lesion were analyzed for LOH events. METHODS: We tested 111 tumor site including DCIS, and invasive, and metastatic lymph nodes from 50 breast cancers for LOH using 5 microsatellite makers on 8 chromosomal arms (3p, 4p, 5q, 8p, 9p, 13q, 17p, & 18q). RESULTS: Twenty-four of 34 breast cancers showing intratumoral histological heterogeneity had common chromosomal losses in the heterogeneous tumor sites, as well as having divergent losses that were restricted to a part of tumor lesion (mean divergent loss, 2.32). The number and frequency of heterogeneous chromosomal losses were not significantly related with age, tumor size, and stage. Overall, at least one chromosomal loss was detected in 48 cases, and incidences of LOH in each chromosome were 27.1~63.3%. A large fraction (58%) of breast cancer patients had 2 to 4 chromosomal losses, and chromosome 8p was most frequently lost (63%). When comparing the number of chromosomal losses in nine cases with all of three progressive lesions, the lost extent was greater in the DCIS (mean losses, 4.44) than in the invasive sites (mean losses, 3.1) and the metastatic lymph nodes (mean losses, 2.9). Moderate-level chromosomal losses involving 3-5 chromosomes were significantly related with lymph node metastasis (p=0.006) and the advanced tumor stage (p<0.005), whereas low-level losses involving 1~2 chromosomes and high-level losses involving 6~7 chromosomes were more common in DCIS and early-stage diseases. CONCLUSION: The DCIS, invasive, and metastatic sites of a breast cancer patient contained common and divergent chromosomal losses. This indicates the concurrent expansion of different subclones was derived from a common ancestor clone, in which an optimal range of chromosomal losses, rather than high-level chromosomal losses, was more frequently associated with lymph node metastasis and the advanced tumor stages.

Classification of Microsatellite Alterations Detected in Endoscopic Biopsy Specimens of Gastric Cancers

PURPOSE: Individual gastric cancers demonstrate complicated genetic alterations. The PCR-based analysis of polymorphic microsatellite sequences on cancer-related chromosomes has been used to detect chromosomal loss and microsatellite instability. For the purpose of preoperative usage, we analyzed the correspondance rate of the microsatellite genotype between endoscopic biopsy and surgical specimens. MATERIALS AND METHODS: Seventy-three pairs of biopsy and surgical specimens were examined for loss of heterozygosity and microsatellite instability by using 40 microsatellite markers on eight chromosomes. Microsatellite alterations in tumor DNAs were classified into a high-risk group (baseline- level loss of heterozygosity: 1 chromosomal loss in diffuse type and high-level loss of heterozygosity: 4 or more chromosomal losses) and a low-risk group (microsatellite instability and low-level loss of heterozygosity: 2 or 3 chromosomal losses in diffuse type or 1~3 chromosomal losses in intestinal type) based on the extent of chromosomal loss and microsatellite instability. RESULTS: The chromosomal losses of the biopsy and the surgical specimens were found to be different in 21 of the 73 cases, 19 cases of which were categorized into a genotype group of similar extent. In 100 surgical specimens, the high-risk genotype group showed a high incidence of nodal involvement (19 of 23 cases: 5 cm) irrespective of tumor size while the incidence of nodal involvement for the low-risk genotype group depended on tumor size (5 of 26 cases: 5 cm). Extraserosal invasion was more frequent in large-sized tumor in both the high-risk genotype group (5 cm: 23 of 24 cases) and the low-risk genotype group (5 cm: 16 of 27 cases). The preoperative prediction of tumor invasion and nodal involvement based on tumor size and genotype corresponded closely to the pathologic tumor stage (ROC area>0.7). CONCLUSION: An endoscopic biopsy specimen of gastric cancer can be used to make a preoperative genetic diagnosis that accurately reflect the genotype of the corresponding surgical specimen.

Alu and L1 Retroelements Are Correlated with the Tissue Extent and Peak Rate of Gene Expression, Respectively

We exploited the serial analysis of gene expression (SAGE) libraries and human genome database in silico to correlate the breadth of expression (BOE; housekeep-ing versus tissue-specific genes) and peak rate of expression (PRE; high versus low expressed genes) with the density distribution of the retroelements. The BOE status is linearly associated with the density of the sense Alus along the 100 kb nucleotides region upstream of a gene, whereas the PRE status is inversely correlated with the density of antisense L1s within a gene and in the up- and downstream regions of the 0-10 kb nucleotides. The radial distance of intranuclear position, which is known to serve as the global domain for transcription regulation, is reciprocally correlated with the fractions of Alu (toward the nuclear center) and L1 (toward the nuclear edge) elements in each chromosome. We propose that the BOE and PRE statuses are related to the reciprocal distribution of Alu and L1 elements that formulate local and global expression domains.

Associations of HLA Alleles with Chronic Infection and Prophylaxis in Vertical Transmission of Hepatitis B Virus

Perinatal transmission and infection of hepatitis B virus (HBV) in early childhood were observed in the offsprings of hepatitis B surface antigen (HBsAg)-positive mothers who had been vaccinated against HBV immediately after giving birth. This prophylaxis failure of perinatal HBV infection is likely due to the interplay of the virus and host immune response. To investigate whether the HLA polymorphism affected the outcome of the perinatal prophylaxis, HLA class I (HLA-A, B and Cw) and class II (HLA-DRB1, DQA1, DQB1 and DPB1) were typed using serology, PCR-SSOP (polymerase chain reaction-sequence specific oligonucleotide probe), and PCR-ARMS (amplification refractory modification system) methods in 22 HBeAg-positive mothers and their 10 prophylaxis-succeeded and 12 prophylaxis- failed children. The HLA types of the mothers and their children were compared with 198 HBsAg-negative healthy controls in a Korean population. HLA-B35 (relative risk=4.2, p<0.01), B51 (relative risk=3.2, p<0.02), DRB1*07 (relative risk=3.8, p<0.03), and DQA1*02 (relative risk=3.8, p<0.03) alleles were more frequent in HBeAg-positive mothers than in the controls. Also, HLA-DRB1*13 (relative risk=0.1, p<0.02) and DPB1*0401 (relative risk=0.1, p<0.02) alleles were less frequent in HBeAg-positive mothers. However, HLA alleles did not affect the outcome of the perinatal prophylaxis against HBV. These results suggest that the reported influences of some HLA alleles on the natural chronic HBV infections may not operate in the HBV infections in children received perinatal prophylaxis.

Seroepidemiological Survey of Hantaan Virus Infection in Sera of Patients at the Kangnam St. Mary Hospital in Korea from 1998 to 2002

Sera of patients visited at the Kangnam St. Mary Hospital in Seoul were collected randomly at the Department of Clinicopathology from January, 1998 to December, 2002. Specimens were collected two twice a month, in a 15-day interval, and 100 specimens were collected at a time. Specimens test in duplicate, and/or displaying antinuclear antibody reaction were excluded from the seroepidemiological analyses. Detection of antibodies to Hantaan virus, an etiologic agent of hemorrhagic fever with renal syndrome (HFRS), was done by indirect immunofluorescent antibody (IFA) technique. Out of 11,361 sera tested, 445 cases (3.9%) showed specific antibody to Hantaan virus. Sexual difference was not noted. Annual incidence of HFRS cases showed a 3 year-periodicity. In the monthly incidence analysis, two peaks of incidence were appeared in the male cases, the first peak in March and the second in August. Female cases showed a single peak in October. The age distribution showed that 64.9% of the sero-positive cases were from 40 to 69 years of age. Peak age-group was in the 6th decade. Each decade of age-group showed diverse patterns of annual and monthly incidences. These results suggest the incidence of HFRS shows a periodicity and a unique pattern in each age group.

Loss of Heterozygosity and PCR Artifacts in a Microsatellite Analysis of Psoriasis and Colorectal Cancer

Although a loss of heterozygosity (LOH) is commonly observed using microsatellite markers in a cell-proliferating malignant disorder, controversial findings of psoriasis, a keratinocyte-outgrowth disease, remain to be explained. It was hypothesized that unstable natures of the microsatellite markers for the polymerase chain reaction (PCR) might give a rise to either a false-positive or -negative LOH. Twentyone frozen skin tissues and 33 formalin-fixed paraffin-embedded archives were obtained from patients with psoriatic plaques and colorectal cancers, respectively. In the frozen psoriatic skin, two of the 17 microsatellite markers selected from 11 chromosomal arms were associated with artifact LOHs that were not reproduced in repeated PCRs. The remaining 15 stable microsatellite markers with few PCR artifacts demonstrated a borderline-level LOH in cases with an ambiguous heterozygosity such as a juxtaposed allelic band. Infrequent LOHs (3 out of 242 heterozygous markers, 1.2%) were detected in psoriatic cases with two separate alleles. In colorectal cancers, a set of the 15 stable microsatellite markers identified a minimal borderline-level LOH at the cut-off point that was same with that of psoriasis. These results indicate that the selection of reproducible microsatellite sequences and the cautious criteria for informative heterozygosity are required to obtain the reliable LOH results from variable genomic DNAs, and that psoriatic lesions harbor few LOH.

The Expression of IL-4 and Interferon-gamma Genes in Peripheral Blood Mononuclear Cells of Patients with Severe Atopic Dermatitis:Evaluation in Proportion to Serum IgE Levels

BACKGROUND: It is not yet clear whether the abnormal cytokine production in relation to serum IgE levels in atopic dermatitis (AD) is associated with the amount of mRNA of cytokine gene. OBJECTIVE: Our purpose was to delineate the effect of reciprocal correlation in the level of mRNA between interleukin-4 (I") and interferon-gamma (IFN-γ) in severe AD. METHODS: We examined 15 cases including 5 AD patients with high serum IgE (>2,000 kU/liter), 5 AD patients with low serum IgE (<100 kU/liter), and 5 healthy controls. Using semi quantitative reverse transcription-polymerase chain reaction, IL-4 and IFN-γ gene expressions in peripheral mononuclear cells (PBMC) were examined. RESULTS: 1) IL-4 gene expression in spontaneous PBMC was higher in AD patient groups than in control group, significantly higher only in AD patient group with high serum IgE level (p < 0.05). 2) IFN-γ gene expression in spontaneous PBMC showed increased tendency in AD patient groups than in control group without statistical significance. 3) IL-4 and IFN-γ gene expressions in stimulated PBMC were not different among all three groups. CONCLUSION: In light of our results, high and low IgE subgroups in AD can exist and AD may not be R characterized by the shift in the reciprocal relationship between IL-4 and IFN-γ when T cells are stimulated under antigen presenting cell-independent conditions.

The relationship between cisplatin-induced apoptosis and p53, bcl-2 and bax expression in human lung cancer cells

OBJECTIVES: Given the roles of bcl-2, bax and p53 in apoptosis, we investigated the effect of their expression on the response to cisplatin in order to understand the molecular events of cisplatin-resistance in lung cancers. METHODS: Three parental human lung cancer cell lines (PC9, PC14 and H69) and their in vitro selected cisplatin-resistant sublines were examined. Cells treated with cisplatin were processed for acridine orange and ethidium bromide staining and DNA gel electrophoresis for the morphologic detection of apoptosis. The endogenous levels of bcl-2, bax and p53 protein expression in lung cancer cells were assessed by Western blot analysis and DNA of polymerase chain reaction-amplified exon 5 to 8 of p53 gene was directly sequenced. RESULTS: H69, which had bcl-2 expression, p53 mutation and decreased expression of p53 and bax, was relatively resistant to cisplatin and delayed and reduced apoptosis. Although apoptosis was markedly reduced in cisplatin-resistant sublines compared to their parental cells, there were no significant differences in the expression of p53, bcl-2 and bax. CONCLUSIONS: Cisplatin-resistance was associated with the reduced cellular susceptibility to apoptosis. Cancer cells with the natural expression of bcl-2 and p53 mutation may be more resistant to cisplatin and less susceptible to apoptosis.

Renewal of Medical School Graduate Courses / 한국의학교육

Over the past years, university administrators have known how hard it is to transform into the modern university. Rigid in-bred research system, narrow interest, unworkable graduate programs are complicatedly woven into a network of academic fraction. Cronyism and protectionism flood various laboratories and research institutes affiliated with the university. Until recently, the department structure of medical school has steadfastly guarded its territory and refused to allow non-medical undergraduate students to apply for the graduate schools of medical science. The graduate schools in medical science are considered just extra appendages because most of graduate students should be engaged in hard work position such as junior faculty or residentship training course of university hospital. In the present environment of graduate program, medical schools are consequently not able to bring in full-time young researchers, but only recently has its door been open for others. It should be time to reorganize the medical school graduate course into large multidisciplinary research group by expanding graduate programs.

The Genetic instability of Gastric Cancer

No abstract available.